# frozen_string_literal: true

require 'rom/initializer'
require 'rom/data_proxy'

module ROM
  # A helper module that adds data-proxy behavior to an enumerable object
  #
  # This module is intended to be used by gateways
  #
  # Class that includes this module can define `row_proc` class method which
  # must return a proc-like object which will be used to process each element
  # in the enumerable
  #
  # @example
  #   class MyDataset
  #     include ROM::EnumerableDataset
  #
  #     def self.row_proc
  #       -> tuple { tuple.each_with_object({}) { |(k,v), h| h[k.to_sym] = v } }
  #     end
  #   end
  #
  #   ds = MyDataset.new([{ 'name' => 'Jane' }, [:name])
  #   ds.to_a # => { :name => 'Jane' }
  #
  # @api public
  module EnumerableDataset
    extend DataProxy::ClassMethods
    include ::Enumerable

    # Coerce a dataset to an array
    #
    # @return [Array]
    #
    # @api public
    alias_method :to_ary, :to_a

    # Included hook which extends a class with DataProxy behavior
    #
    # This module can also be included into other modules so we apply the
    # extension only for classes
    #
    # @api private
    def self.included(klass)
      return unless klass.is_a?(::Class)

      klass.class_eval do
        extend Initializer
        include DataProxy

        param :data
      end
    end

    forward :take

    %i[
      chunk collect collect_concat drop_while find_all flat_map
      grep map reject select sort sort_by take_while
    ].each do |method|
      class_eval(<<-RUBY, __FILE__, __LINE__ + 1)
        def #{method}(...)                         # def collect(...)
          return to_enum unless block_given?       #   return to_enum unless block_given?
          self.class.new(super(...), **options)    #   self.class.new(super(...), **options)
        end                                        # end
      RUBY
    end
  end
end
